Re: Can I simulate a weak conflict?

[Nicolas Boullis <nboullis@debian.org>]

Hi,

On Thu, Jul 28, 2005 at 07:12:16AM +1000, skaller wrote:
> 
> Two methods, one is not tenable:
> 
> (a) X conflicts with no-X implicitly
> (b) When Y depends on no-X, if Y is installed, no-X is
>   synthesised and installed too if it doesn't exist, 
>   (and conflicting with X to prevent X being installed).
> 
> The dummy installation is mandatory because here
> is the alternative, which is not tenable:
> 
> When installing X, scan all installed packages
> to see if there is a dependency on no-X, if so
> there is a conflict.
> 
> This is untenable because it requires scanning all
> packages in your local database, whereas installation
> of a package should only require looking up the 
> listed dependencies.
> 
> The reason a logical 'X isn't installed' does not
> work is that you could install Y, which depends 
> on no X, and then just install X. Now Y is silently
> broken by a package that knows nothing about Y.

As far as I know, such things already happen with conflicts: let foo 
conflict with bar. If you install foo first, everything is fine. Later, 
if you install bar, foo is broken by bar, while bar knows nothing about 
foo... Where's the difference?


Nicolas